DWC root temps question.

[Chrellyboy]

Hi there,

I have read somewhere that the root temp of DWC should not exceed 21 degrees celcius because it apparantly makes the water less capable of holding oxygen. Is this correct?

Would I get problems with a water temp ranging from 22-28c if I use a 180L/H airpump per plant?

Sadly, I have no way of lowering the temperature. I do not want to sleep in a freezer!

Thank you very much in advance

ChrellyBoy

 

[Outportgrower]

Hi there,

I have read somewhere that the root temp of DWC should not exceed 21 degrees celcius because it apparantly makes the water less capable of holding oxygen. Is this correct?

Would I get problems with a water temp ranging from 22-28c if I use a 180L/H airpump per plant?

Sadly, I have no way of lowering the temperature. I do not want to sleep in a freezer!

Thank you very much in advance

ChrellyBoy

No need to sleep in a freezer when you can just buy a chiller. That will keep everything at a steady temp year round.

 

[Haps]

Sorry I don't speak celsius, in dwc 68-72f is the acceptable, or optimal temps. Above 73, the DO is very low, your pump should keep the water ok with DO, but heat brings on pathogen growth as well. You will see growers here who do grow with high temps successfully, but mostly too much heat causes reduced health and or plant death, and yes I have seen that with my own eyes in my own grow. If you grow with small lights, you might have a bit easier time as the metabolism of the plants is lower and take less resources to grow. Insulation is our friend, controling your environment is the place to start, look at what options you do have. Good luck.
H

 

[fatigues]

Hi there,

I have read somewhere that the root temp of DWC should not exceed 21 degrees Celsius because it apparently makes the water less capable of holding oxygen. Is this correct?

Correct that lower temp water holds more soluble oxygen. Incorrect that this is the primary reason you want your rez temps to be low. The main reason for this is that once temps sneak up to 70+, the chances of root rot and other fungal/microbial problems increases significantly.

There are divided opinions on the best temp for a rez. Many on ICMag would prefer 65 degrees F. There are others who aim for 55-63F, targeting 58F as their main "goal". YMMV.

Would I get problems with a water temp ranging from 22-28c if I use a 180L/H air pump per plant?

Maybe - maybe not. Freezerboy has noted he has experienced no problems in a DWC with rez temps in the high 80s and low 90s. He's the first person to agree that this is not ideal and he would much rather not be having these sorts of temperatures if he could help it. Point is - his plant roots survived those temps none the worse for wear.

Would you be okay at those temps? Maybe. There are a large number of posters on ICM who have got away with it; and many more who have had significant root rot issues with temps that high too. Some have lost their entire grow due to the problem. As to what would happen with your grow - it's a crap shoot. Nobody knows. It certainly is best to avoid those high temps though - and absolutely nobody here is going to suggest that you should not try to.

Question is: at what cost and by what means do you avoid those rez temps?

Sadly, I have no way of lowering the temperature. I do not want to sleep in a freezer!

Actually, you do, but water temperature control is expensive. The standard approach is to buy a water chiller from an Aquarium store, appropriately rated for your rez size. Please note that aquarium water chillers are expensive and can get significantly expensive to deliver, too.

There are some DIY attempts that borg various pedestal and big bottle style water coolers in an attempt to use it as a chiller on the cheap. They look like absolute crap and don't fit well in a cabinet - but some of them work.

Others have tried to use mini refrigerators (dorm room/bar fridge style) to accomplish the same goal. Older ones would be better for this approach as the newer ones have the radiator coils wrapped around the fridge internally and enmeshed in injected foam - instead of just attached to the back of the fridge like a standard black fridge radiator coil.

The few users that have managed to get either type to work would agree that the result was large, unwieldy and a complete pain in the ass to kludge a DIY out of a bar fridge. Their projects came about as a result of the significant cost for an aquarium chiller; they were not undertaken because aquarium chillers don't work well. They do work - but at a cost.

That said, your best bet is to just bite the bullet and get a small aquarium chiller, say 1/10 horsepower if that's good enough for your rez size. Water chillers are relatively expensive kit (sometimes the single most expensive kit you have to buy) for your hydro setup.

On the plus side, they are essentially maintenance free and should work as long and as reliably as any fridge. Most require a separate sump/inline pump to get water to and from your rez to the chiller and back. The pumps and tubing is pretty cheap, but do recognize that it is an additional cost above the chiller.

Check your local Craigslist, btw, paying special attention to used Aquarium setups. Real bargains to be had there when it comes to chillers.

Unless your rez is very very small, you want to avoid a Peltier style thermodynamic cooling as that is highly energy inefficient and won't effectively cool your rez unless it's damn small. You want a standard compressor style chiller, preferably with a titanium exchange.

 

[Ninjaaa]

volume of bucket(L)/2*60 = xxx L/h, amount of air needed for very good oxigination of nutrient solution

 

[Chrellyboy]

Thanks everyone for your inputs! I have decided it is probably easyer and cheaper to use Ebb/Flood. I mean, a temperature controller costs easily 400-500$, which is just crazy. I could get some pretty nifty aeroponic gear for that kind of money.

Correct that lower temp water holds more soluble oxygen. Incorrect that this is the primary reason you want your rez temps to be low. The main reason for this is that once temps sneak up to 70+, the chances of root rot and other fungal/microbial problems increases significantly.

Root rot happens because of the decreased oxygen levels as far as I know . Roots dont have problems with high temperatures in soil. But thank you very much for your reply, it was very informative and must have taken a great while to write! I appreciate it a lot!